File: coreutils.info,  Node: The uniq command,  Next: Putting the tools together,  Prev: The sort command,  Up: Opening the software toolbox

The ‘uniq’ Command
==================

Finally (at least for now), we’ll look at the ‘uniq’ program.  When
sorting data, you will often end up with duplicate lines, lines that are
identical.  Usually, all you need is one instance of each line.  This is
where ‘uniq’ comes in.  The ‘uniq’ program reads its standard input.  It
prints only one copy of each repeated line.  It does have several
options.  Later on, we’ll use the ‘-c’ option, which prints each unique
line, preceded by a count of the number of times that line occurred in
the input.